https://sites.google.com/site/prologsite/prolog-problems/1 problem 1.07

flatten_lists.py

# -*- coding: utf-8 -*-

from __future__ import (absolute_import, division, unicode_literals)

def flat_list(l):
    result = []
    for i, e in enumerate(l):
        if type(e) is list:
            result += e
        else:
            result += [e]
    if len(result) == 1:
        return result[0]
    return result

def test_simple_list(l):
    return all(map(lambda i: not isinstance(i, list), l))

if __name__ == '__main__':
    origin = ['a', [['b'], 'c', ['d', ['e']]]]
    print origin
    while not test_simple_list(origin):
        origin = flat_list(origin)
        print origin